I recently upgraded my Zotero storage plan, but file syncing is not working.

My attachments are stored locally under Zotero/storage/... (not linked files).
File syncing is enabled, and I am logged into the correct account.
Sync completes quickly but no attachments are uploaded, and nothing appears in the web library or iPad app.

I have already tried logging out/in, restarting Zotero, and verifying all sync settings.

At this point I believe my account may have a stalled server-side file sync state after the upgrade.

I would appreciate help resetting this.